Question: Find the value of $\frac{5x+9y}{45xy}$, given $x = \frac{3}{5}$ and $y = \frac{7}{9}$.
We substitute the values for $x$ and $y$ into the expression and get $$\frac{5\left(\frac35\right)+9\left(\frac79\right)}{45\left(\frac35\right)\left(\frac79\right)}=\frac{3+7}{3\cdot7}=\boxed{\frac{10}{21}}.$$